I'm about to make 100 or so flower pots from 2 liter soda bottles, and was considering building a small reservoir into the bottom of each. My idea is to keep the plants from drying out too rapidly if the soilless mix holds too little water. I would be giving many of these these plants away, and expect some recipients to water them unreliably, and plant them into the ground late, or never. So the longer they can survive with marginal care, the better.
I'm a total newbie to EBs and HEBs, and not super-experienced with growing in pots or planters. I'm hoping for advice from people who know how these reservoirs work in practice.
What I do best is over-watering seedling in small cells, so I worry about drainage.
- I would drill or melt 1/4" holes about 1 1/2 inches up from the bottom of the 2 liter bottle, so there would be a small water reservoir.
- My "colander" would be the bottom 2" cut from a much smaller bottle, inverted and drilled with several small holes.
- The circumference between the small inverted bottle bottom and the 2 liter bottle bottom would be my wick.
- I'm planning for them to be top-watered until the reservoir fills, and some comes out the sides.
Since I use a fast-draining mix with lots of small bark nuggets, I worried about its ability to wick water all the way up a 7 inch soil column. I am considering adding a 6" strip of cotton flannel as a literal "wick". Or that might be an unnecessary concern.
If I don 't worry about aeration through the 7 inch deep soil, I might use more peat and pine fines (dust and small fibers). Then it would hold more water but the bottom few in c hes might become anaerobic.
I've seen a lot of the 2-litre, self-watering setups where the bottle is cut about in half and the top inverted. Since you are using a chunky substrate I think the idea of using a wick is a good plan. I don't know if this link will post, but here's a similar version with a wine bottle. I think I'll try a few of these with some glass bottles I have. http://www.etsy.com/listing/74576009/self-watering-planter-m...
This is a good tutorial I would recommend. Steer clear of any design that has all your potting mix sitting directly in the reservoir. The wick in this design will draw the water up into the soil bed. There has to be an air space between the bottom of the soil and the top of the water in the reservoir.
The only adjustment I would make to this design (to increase the reservoir capacity) would be to drill a hole through the reservoir, parallel to where the top screws on. Once the reservoir is filled to capacity, any excess water will drain out of the hole before it hits the bottom of the soil bed. This will increase the reservoir holding capacity.
>> 2-litre, self-watering setups where the bottle is cut about in half and the top inverted.
I saw a You-Video like that and didn't like the design. I'm hoping to come up with something as simple as possible, and I'm just aiming for a few ounces of water that will allow a little longer between waterings,
>> Steer clear of any design that has all your potting mix sitting directly in the reservoir. The wick in this design will draw the water up into the soil bed. There has to be an air space between the bottom of the soil and the top of the water in the reservoir.
That makes sense to me: submerged soil means drowned roots. I based my idea on the "inverted colander in a 5-gallon bucket" classic design. At least that way, the drown-root-zone is only a narrow strip of soilless mix.
>> Since you are using a chunky substrate I think the idea of using a wick is a good plan.
Sigh! Too bad. But I will probably make most of them that way, and add more bark fines and peat to the bottom 1/3 of any where I leave the wick out.
Any suggestions for wick material other than cotton flannel? All I saw in the link above were some photos, not instructions.
"Everything should be made as simple as possible, but not simpler."